"We’re here to lend our support to your movement," said Eric Howk of Portugal. The Man. "This is a crowd that represents incredible bravery and progress."

The performance included a special appearance from rapper Black Thought, a member of The Roots. Watch the performance

The national demonstration came just a little more than a week after students held a national walkout for 17 minutes, to recognize the 17 people killed during the shooting at Marjory Stoneman Douglas High School in Parkland, Fla.